The present invention relates to routing in connection-oriented networks, such as Asynchronous Transfer Mode (ATM) networks and proprietary Passport Path Oriented Routing Systems (PORS). More particularly, the present invention relates to mapping many connections with the same performance objectives onto a single connection, and transporting (also known as shunting) the data through the underlying network infrastructure.
In a conventional ATM-centric network providing end-to-end connectivity for users of data services or protocols such as Frame Relay or Internet Protocol (IP), the number of connections can become quite large. Thus, the management of such connections becomes increasingly complex, and scaleability of networks becomes problematic.
Performance is also an issue in such networks. If connection-oriented transport is used for services and protocols such as Frame Relay or IP, performance is affected adversely because each connection requires setup time as the route is often determined by software. Also, significant CPU resources at tandem switches are required as the Virtual Path Identifier/Virtual Channel Identifier (VPI/VCI) space becomes large. Additionally, if connectionless transport is used, performance and routing decisions at each hop in the connectionless network are affected by the additional need to segment and reassemble frames.
It is desirable, therefore, to provide a scheme for transporting data such as Frame Relay and IP traffic across an ATM-centric network that addresses the above performance and management issues. It is also desirable to provide such a scheme that is easy to provision. More specifically, it is desirable to provide such a scheme that reduces the number of connections in the network and utilizes high performance switching capabilities of the network.
This invention satisfies those desires by providing a mechanism for multiplexing multiple connections sharing the same performance objectives onto one virtual connection, and shunting the data through the underlying network infrastructure.
A system consistent with the present invention comprises a switch in a connection-oriented network for establishing a path through a network to a remote switch for a plurality of connections between the switch and the remote switch, the switch comprises an end point of the path; a networking interface comprises means for receiving a setup request from the end point; means for determining a route through the network for the path and means for transmitting a setup request to the remote switch via the network.
A method consistent with the present invention establishes a path through an connection-oriented network for a plurality of connections between a first and second switch in the network, each connection having a performance objective, by determining the route of the path over the network between the first and second switch using a routing protocol; establishing the path between the first and second switch; and multiplexing the ones of the connections having the same performance objective onto the path between the first and second switch.
Apparatus and networks are also provided for carrying out the methods consistent with the present invention.
The advantages accruing to the present invention are numerous. The present invention provides a high-performance, low-latency method for routing traffic across connection-oriented networks, such as ATM-centric networks. Methods consistent with the present invention eliminate the need for software routing on tandem switches. There is no need to go up the protocol routing stack at each hop. Advantageously, the present invention operates independently of the routing protocol and makes direct use of the underlying layer 2 forwarding.
The above desires, other desires, features, and advantages of the present invention will be readily appreciated by one of ordinary skill in the art from the following detailed description of the preferred implementations when taken in connection with the accompanying drawings.